📚 Year 7 SQA Biology: Formula & Key Concepts Quick Reference Guide | 七年级 SQA 生物：公式定理速查手册
Welcome to your ultimate quick reference guide for Year 7 SQA Biology. This handbook brings together the essential formulas, word equations and key principles you need to memorise for your assessments. Keep it handy as you revise cells, respiration, photosynthesis and the other fundamental topics covered in the Scottish Curriculum for Excellence.
欢迎使用这本七年级 SQA 生物公式定理速查手册。我们为你整理了评估中必须掌握的核心公式、文字方程式和重要原理。复习细胞、呼吸、光合作用以及苏格兰卓越课程其他基础主题时，请随身携带这份指南。
1. Magnification Formula | 放大倍率公式
nification = Image size divided by Actual size. Always make sure both measurements are in the same unit, usually millimetres (mm) or micrometres (µm).
使用显微镜时，你可以计算出图像相比实物放大了多少倍。关系很简单：放大倍率 = 图像尺寸 ÷ 实际尺寸。请务必确保两个测量值使用相同单位，通常为毫米或微米。
Magnification = Image size (I) ÷ Actual size (A)
放大倍率 = 图像尺寸 (I) ÷ 实际尺寸 (A)
ion is 20 ÷ 0.2 = 100×. You can also rearrange the formula to find actual size: A = I ÷ M.
例如，如果细胞图像的测量尺寸为 20 mm，而实际细胞是 0.2 mm，则放大倍率为 20 ÷ 0.2 = 100×。你也可以对公式变形求实际尺寸：A = I ÷ M。
| Symbol | Meaning | Unit example |
|---|---|---|
| M | Magnification | times (×) |
| I | Image size | mm, µm |
| A | Actual size | mm, µm |
2. Photosynthesis Word Equation | 光合作用文字方程式
Photosynthesis is the process by which green plants, algae and some bacteria use light energy to convert carbon dioxide and water into glucose and oxygen. Chlorophyll in chloroplasts captures sunlight to power the reaction.
光合作用是绿色植物、藻类和某些细菌利用光能，将二氧化碳和水转化为葡萄糖和氧气的过程。叶绿体中的叶绿素捕获阳光为反应供能。
Carbon dioxide + Water → Glucose + Oxygen
二氧化碳 + 水 → 葡萄糖 + 氧气
r 7 you mainly need to recall the word equation and that light and chlorophyll are required.
用符号表示时常写作：6CO₂ + 6H₂O → C₆H₁₂O₆ + 6O₂，但七年级只需要记住文字方程式以及需要光和叶绿素。
- The glucose produced can be used for respiration, stored as starch, or turned into cellulose for cell walls.
- 产生的葡萄糖可用于呼吸、以淀粉形式储存或转化为纤维素构建细胞壁。
3. Aerobic Respiration Equation | 有氧呼吸方程式
Aerobic respiration is the chemical reaction that releases energy from glucose in the presence of oxygen. It occurs continuously in most cells, especially in mitochondria, and produces carbon dioxide and water as waste.
有氧呼吸是在有氧条件下从葡萄糖中释放能量的化学反应。它持续发生在大多数细胞的线粒体中，并产生二氧化碳和水作为废物。
Glucose + Oxygen → Carbon dioxide + Water (+ energy)
葡萄糖 + 氧气 → 二氧化碳 + 水 (+ 能量)
symbol equation is C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O, but you primarily need the word equation.
释放的能量用于肌肉收缩、构建大分子、维持体温等生命活动。配平的符号方程式为 C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O，但你主要需掌握文字方程式。
4. Anaerobic Respiration in Animals | 动物无氧呼吸
When oxygen is limited, animal cells can respire anaerobically to release a small amount of energy. This produces lactic acid, which can build up in muscles and cause fatigue and cramp.
当氧气不足时，动物细胞可进行无氧呼吸释放少量能量。此过程产生乳酸，乳酸在肌肉中累积会引起疲劳和抽筋。
Glucose → Lactic acid (+ energy)
葡萄糖 → 乳酸 (+ 能量)
Anaerobic respiration in animals does not produce carbon dioxide or water. After exercise, oxygen is needed to break down the lactic acid – this is called 'repaying the oxygen debt'.
动物的无氧呼吸不产生二氧化碳和水。运动后需要氧气分解乳酸，这被称为'偿还氧债'。
5. Anaerobic Respiration in Plants and Yeast | 植物与酵母的无氧呼吸
Plants and yeast cells can also respire without oxygen, but the products are different. They produce ethanol and carbon dioxide instead of lactic acid. This type of anaerobic respiration is exploited in baking and brewing.
植物和酵母细胞也可在无氧条件下呼吸，但产物不同。它们生成乙醇和二氧化碳，而非乳酸。这种无氧呼吸被用于烘焙和酿造工业。
Glucose → Ethanol + Carbon dioxide (+ energy)
葡萄糖 → 乙醇 + 二氧化碳 (+ 能量)
In yeast, this reaction is called fermentation. The carbon dioxide makes bread rise, while ethanol contributes to the flavour and preservation of alcoholic drinks.
酵母中的这一反应称为发酵。二氧化碳使面包膨胀，而乙醇则赋予酒精饮料风味并起防腐作用。
6. Rate of Reaction | 反应速率公式
In biology, you often need to measure how quickly a process happens, such as the rate of photosynthesis or the rate of enzyme activity. The basic formula for any rate is the amount of change divided by time.
在生物学中，你经常需要测量一个过程发生的快慢，例如光合作用速率或酶活性速率。任何速率的通用公式都是变化量除以时间。
Rate = Amount of product made (or substrate used) ÷ Time
速率 = 生成的产物量 (或消耗的底物量) ÷ 时间
le to interpret graphs showing how rates change when conditions like light intensity, temperature or pH vary.
例如，若实验在 5 分钟内产生 30 cm³ 氧气，则速率为 30 ÷ 5 = 6 cm³/min。你应能解读展示速率随光照强度、温度或 pH 值等条件变化而变化的曲线图。
7. Energy Transfer in Food Chains | 食物链中的能量传递
Energy is transferred along food chains from producers to consumers, but much of it is lost at each trophic level. A useful 'rule of thumb' is that only about 10% of the energy is passed on to the next level; the rest is used for life processes, released as heat, or lost in wastes.
能量沿食物链从生产者传递到消费者，但每个营养级都会损失大量能量。一个有用的经验法则是，大约只有 10% 的能量传递给下一营养级；其余用于生命活动、以热的形式散失或随废物排出。
Approximate energy transfer efficiency ≈ 10%
能量传递效率近似值 ≈ 10%
This explains why food chains rarely have more than four or five trophic levels: there simply is not enough energy left to support another level. Biomass pyramids reflect the same loss of mass and energy up the chain.
这解释了为什么食物链很少超过四到五个营养级：剩余能量不足以支撑另一个级别。生物量金字塔同样反映了随营养级上升质量与能量的损失。
8. Diffusion and Osmosis – Key Principles | 扩散与渗透——关键原理
Diffusion is the net movement of particles from a region of higher concentration to a region of lower concentration, down a concentration gradient, until equilibrium is reached. No energy is required – it is a passive process. Oxygen entering blood in the lungs and carbon dioxide leaving leaves are examples.
扩散是指粒子沿浓度梯度由高浓度区域向低浓度区域的净移动，直至达到平衡。该过程不消耗能量，属于被动运输。氧气进入肺部血液和二氧化碳从叶片排出都是扩散的例子。
Osmosis is a special case of diffusion: the movement of water molecules across a selectively permeable membrane from a dilute solution (high water potential) to a more concentrated solution (low water potential).
渗透是扩散的一种特殊情况：水分子通过选择透过性膜，从稀溶液（高水势）向较浓溶液（低水势）移动。
| Process | Particles moved | Membrane | Energy |
|---|---|---|---|
| Diffusion | Solute or gas particles | Cell membrane not always required | Passive |
| Osmosis | Water molecules only | Selectively permeable membrane | Passive |
9. The Lock and Key Model of Enzyme Action | 酶作用的锁钥模型
Enzymes are biological catalysts made of protein that speed up chemical reactions in living organisms. The 'lock and key' model describes how the active site of an enzyme has a specific shape that fits only a matching substrate, just like a key fits a specific lock.
酶是由蛋白质构成的生物催化剂，能加速生物体内的化学反应。'锁钥模型'描述了酶的活性部位具有独特形状，只与相匹配的底物结合，犹如钥匙插入特定的锁。
Enzyme + Substrate → Enzyme-substrate complex → Enzyme + Products
酶 + 底物 → 酶-底物复合物 → 酶 + 产物
Factors such as temperature and pH affect enzyme activity. If the shape of the active site changes (denaturation), the substrate can no longer fit and the enzyme stops working. Most human enzymes work best around 37 °C and at a specific pH range.
温度和 pH 等因素会影响酶活性。如果活性部位的形状改变（变性），底物便无法结合，酶随即失效。大多数人体酶的最适温度在 37 °C 左右，并有特定的 pH 范围。
10. Balanced Diet – Key Nutrient Functions | 均衡膳食——关键营养素功能
A balanced diet provides all the essential nutrients in the right proportions. The main groups are carbohydrates (for energy), proteins (for growth and repair), lipids/fats (for energy storage and insulation), vitamins and minerals (for various body functions), fibre (for digestion) and water.
均衡膳食以正确的比例提供所有必需营养素。主要类别包括：碳水化合物（供能）、蛋白质（生长与修复）、脂类/脂肪（能量储存与隔热）、维生素和矿物质（多种生理功能）、膳食纤维（助消化）以及水。
You can test for some nutrients using simple indicators. Starch turns iodine solution blue-black, reducing sugars turn Benedict's solution orange-red when heated, proteins turn Biuret reagent purple, and lipids produce a translucent spot on filter paper.
你可以用简单指示剂检测某些营养素：淀粉遇碘液呈蓝黑色，还原糖与班氏试剂加热后呈橘红色，蛋白质遇双缩脲试剂呈紫色，脂类在滤纸上留下半透明斑点。
| Nutrient | Test | Positive result |
|---|---|---|
| Starch | Iodine solution | Blue-black |
| Reducing sugars | Benedict's solution + heat | Orange-red precipitate |
| Protein | Biuret reagent | Purple/lilac |
| Lipids | Ethanol then water (emulsion test) | Cloudy white emulsion |
11. Key Cell Organelles and Their Functions | 关键细胞器及其功能
Knowing the parts of plant and animal cells is essential for Year 7. Animal cells contain a nucleus (controls the cell, contains genetic material), cytoplasm (where chemical reactions occur), cell membrane (controls what enters and leaves) and mitochondria (site of aerobic respiration). Plant cells also have a rigid cell wall made of cellulose, a large permanent vacuole (stores sap), and chloroplasts (contain chlorophyll for photosynthesis).
对于七年级，了解动植物细胞的各个部分是必要的。动物细胞包括细胞核（控制细胞，含遗传物质）、细胞质（化学反应场所）、细胞膜（控制物质进出）和线粒体（有氧呼吸场所）。植物细胞还有由纤维素构成的坚韧细胞壁、大液泡（储存细胞液）以及叶绿体（含叶绿素，进行光合作用）。
Organelles such as ribosomes (protein synthesis) are introduced in later years, but you should now be confident comparing plant and animal cells and explaining how specific structures relate to their functions.
诸如核糖体（蛋白质合成）等细胞器会在以后学年介绍，但你现在应能熟练比较动植物细胞，并解释特定结构如何与其功能相适应。
12. The Carbon Cycle – Key Transfers | 碳循环——关键传递过程
The carbon cycle shows how carbon moves between the atmosphere, organisms, oceans and the Earth's crust. Key processes you need to know include photosynthesis (removes CO₂ from the air), respiration and combustion (return CO₂ to the air), feeding (passes carbon compounds along food chains), decomposition (microorganisms break down dead matter, releasing CO₂), and fossilisation (locks carbon underground).
碳循环展示了碳在大气、生物、海洋和地壳之间的转移过程。你需要掌握的关键过程包括：光合作用（从空气中移除 CO₂）、呼吸和燃烧（将 CO₂ 归还大气）、摄食（将碳化合物沿食物链传递）、分解作用（微生物分解死物并释放 CO₂）以及化石形成（将碳封存于地下）。
Remembering these processes helps you explain how carbon is recycled and why deforestation or burning fossil fuels increases atmospheric CO₂, contributing to climate change.
记住这些过程可以帮助你解释碳如何循环，以及为什么森林砍伐或燃烧化石燃料会增加大气中的 CO₂，进而引起气候变化。
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